diff --git a/src/exchange.ts b/src/exchange.ts
new file mode 100644
index 0000000..c53e963
--- /dev/null
+++ b/src/exchange.ts
@@ -0,0 +1,9 @@
+import { Account } from "./interface/account";
+import {Quote} from "./interface/quote"
+
+interface Exchange {
+    name: string;
+
+    fetchAccounts: () => Account[];
+    fetchQuote: (symbol: string) => Quote;
+}
\ No newline at end of file
diff --git a/src/interface/account.ts b/src/interface/account.ts
new file mode 100644
index 0000000..97e3ea6
--- /dev/null
+++ b/src/interface/account.ts
@@ -0,0 +1,3 @@
+export interface Account {
+    fetchPortfolio: () => Portfolio;
+}
\ No newline at end of file
diff --git a/src/interface/portfolio.ts b/src/interface/portfolio.ts
new file mode 100644
index 0000000..15706e9
--- /dev/null
+++ b/src/interface/portfolio.ts
@@ -0,0 +1,17 @@
+export interface Position {
+    readonly symbol: string;
+
+    readonly quantity: number;
+
+    readonly dateAcquired: Date;
+
+    readonly pricePaid: number;
+    readonly price: number;
+
+    readonly change: number;
+    readonly changePct: number;
+}
+
+export interface Portfolio {
+    readonly positions: Position[];
+}
\ No newline at end of file
diff --git a/src/interface/quote.ts b/src/interface/quote.ts
new file mode 100644
index 0000000..fd84a23
--- /dev/null
+++ b/src/interface/quote.ts
@@ -0,0 +1,3 @@
+export class Quote {
+    
+}
\ No newline at end of file